Variable flow heating system with heating accessories placed in series

ABSTRACT

Heating systems including a boiler for heating a heating fluid, a plurality of heating accessories each requiring input of heat, piping connecting the boiler with the heating accessories, at least one of the heating accessories being placed in series relative to at least one other of the heating accessories, and a valve system including a variable speed pump and an associated control system for varying flow of the heating fluid from the boiler. Each heating accessory is configured such that heating fluid from the boiler delivered through the piping to each successive heating accessory provides heat to each heating accessory and the heating fluid is returned to the boiler at a sufficiently low temperature (e.g., no more than about 120° F.) so as to allow the returned heating fluid to be used to condense water out of flue gas generated by the boiler so as to maximize the efficiency of the boiler.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/391,118 filed Oct. 8, 2010 and entitled VARIABLEFLOW HEATING SYSTEM WITH HEATING ACCESSORIES PLACED IN SERIES, hereinincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

This invention relates to heating systems.

2. Background and Relevant Art

Modern society relies on heating systems for providing heat employed fora wide variety of uses. For example, residential and commercialproperties include heating systems for providing heated water forindustrial and culinary uses, heating of swimming pools, and hot tubs,as well as space heating. Relatively large properties, such ascondominiums, hotels, and recreation centers often have a plurality ofsuch accessories (e.g., culinary water, swimming pools, hot tubs, etc.),that each require heating.

Within such properties, it would be an advantage in the art to provideenergy systems with increased efficiency so as to lower energyconsumption and thus costs while continuing to meet the needs presentedby typical accessories included within such properties.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to heating systems including a boilercomprising a heat exchanger for heating a heating fluid, a plurality ofheating accessories each requiring input of heat, piping connecting theboiler with the heating accessories, at least one of the heatingaccessories being placed in series relative to at least one other of theheating accessories, and a valve system and associated control systemfor varying flow of the heating fluid from the boiler through the pipingto the heating accessories. The valve system may comprise a variablespeed pump. Each heating accessory may include a heat exchanger suchthat heating fluid from the boiler and delivered through the piping toeach successive heating accessory in series provides heat to eachheating accessory and the heating fluid is returned to the boiler at asufficiently low temperature (e.g., no more than about 120° F.) so as toallow the returned heating fluid to be used to condense water out offlue gas generated by the boiler so as to maximize the efficiency of theboiler.

In one embodiment, each heating accessory may include a heat exchangerfor exchanging heat from the heating fluid to another material. Inanother embodiment, one or more of the heating accessories may simplycomprise a heating load (i.e., requiring input of heat) such asproviding radiant heat to a building or other space, melting snow, etc.

Arrangement of the various heating accessories in series, as well asproviding a valve system and associated variable speed pump and controlsfor varying the flow rate of heating fluid out of the boiler providesfurther efficiencies to the overall system. For example, in oneembodiment, the heating accessories (e.g., each representing a loadrequiring input of heat, such as culinary hot water, a hot tub, a heatedswimming pool, radiant heat, snow melting, etc.) are arranged in serieswith the heating accessory having the highest desired target temperatureplaced first in the series and the other heating accessories arranged indecreasing order such that the heating accessory having the lowestdesired target temperature is placed last in series.

These and other benefits, advantages and features of the presentinvention will become more fully apparent from the following descriptionand appended claims, or may be learned by the practice of the inventionas set forth hereinafter

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by references to specific embodiments thereof, which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a flow chart describing the present systems and methods;

FIG. 2 is a schematic diagram of an exemplary heating system; and

FIG. 3 is a schematic diagram of another exemplary heating system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Definitions

As used in this specification and the appended claims, the singularforms “a,” “an” and “the” include plural referents unless the contextclearly dictates otherwise.

II. Introduction

The present invention is directed to heating systems including a boilercomprising a heat exchanger for heating a heating fluid, a plurality ofheating accessories each requiring input of heat, piping connecting theboiler with the heating accessories, at least one of the heatingaccessories being placed in series relative to at least one other of theheating accessories, and a valve system and associated variable speedpump and a control system for varying flow of the heating fluid from theboiler through the piping to the heating accessories. Each heatingaccessory includes a heat exchanger such that heating fluid from theboiler and delivered through the piping to each successive heatingaccessory in series provides heat to each heating accessory and theheating fluid is returned to the boiler at a sufficiently lowtemperature (e.g., no more than about 120° F.) so as to allow thereturned heating fluid to be used to condense water out of flue gasgenerated by the boiler so as to maximize the efficiency of the boiler.

Arrangement of the various heating accessories or systems in series, aswell as providing a valve system including a variable speed pump, aswell as associated controls for varying the flow rate of heating fluidout of the boiler provides further efficiencies to the overall system.For example, in one embodiment, the heating accessories (e.g., eachrepresenting a load requiring input of heat, such as culinary hot water,a hot tub, a heated swimming pool, etc.) are arranged in series with theheating accessory having the highest desired target temperature placedfirst in the series and the other heating accessories arranged indecreasing order such that the heating accessory having the lowestdesired target temperature is placed last in series.

In such an embodiment, the heating fluid (e.g., water) from the boileris routed through the piping to the heating accessory having the highesttarget temperature, where the heating fluid heats water or othermaterial to the desired target temperature within the heat exchanger ofthe first heating accessory. The somewhat cooler heating fluid thencontinues on to the second heating accessory, where the heating fluidthen heats water or other material to the desired target temperaturewithin the heat exchanger of the second heating accessory. The heatingfluid thus continues on through the system, providing heat to each ofthe heating accessories within the heating system. After the finalheating accessory, the heating fluid has been cooled to a sufficientlylow temperature (e.g., no more than about 120° F.) that will allowcondensation of water within the boiler flue gas. At this stage, therelatively cool heating fluid is routed back to the boiler, where it isused to condense out water vapor within the flue gas.

Condensation of the water vapor within the flue gas allows the boiler tooperate at significantly higher efficiency. For example, when a boilerheats a heating fluid (e.g., by combustion of natural gas or otherfuel), hot flue gas is generated. As a result of combustion ofhydrocarbons, water vapor is one of the reaction products formed. Suchwater vapor represents a significant amount of latent heat, as it takessignificant heat to convert the water into vapor form (e.g., as a resultof the relatively high heat capacity and heat of vaporization of water).By way of example, a boiler may achieve about 80% efficiency, althoughhigher efficiency is not generally possible without retrieving heatwithin the water vapor within the flue gas. By condensing such watervapor within the flue gas so as to recover this heat, significantlyhigher efficiencies can be achieved (e.g., at least about 90%, at leastabout 95% percent, or even higher).

III. Exemplary Heating Systems and Methods

FIG. 1 is a flow chart illustrating an exemplary method. As indicated atS10, a heating fluid (e.g., water, gycol, etc.) is heated within aboiler. As indicated at S12, the heating fluid is then delivered througha variable flow rate system from the boiler to a plurality of heatingaccessories placed in series relative to one another. As indicated atS14, the heating fluid is returned to the boiler at a sufficiently lowtemperature to allow condensation of water from the boiler flue gas.

FIG. 2 illustrates a relatively simple exemplary heating system 100including a boiler 102. Boiler 102 includes a heat exchanger for heatinga heating fluid. Piping 104 conveys the heating fluid out of boiler 102through a variable flow rate valve and control system 106 which isconfigured to selectively vary the flow rate of the heating fluid out ofboiler 102 and through piping 104 to the various downstream heatingaccessories. For example, the variable flow rate valve and controlsystem 106 may be configured to have a turn down ratio of at least about10:1. The turn down ratio refers to the ratio of maximum flow raterelative to the minimum flow rate that can be provided by the systemwithout damage to the boiler. For example, a 10:1 turn down ratio refersto a system that is capable of reducing the flow rate of heating fluidat a given temperature to only one-tenth that of the maximum flow,without damage to the boiler.

Such a configuration is particularly advantageous as by reducing theflow rate of heating fluid through the system, the temperature of theheating fluid returning to the boiler will be lower than it would butfor the reduction in flow rate. This results as the amount of heatcapable of being transferred out of the heating fluid is a function ofits temperature and volume (or flow rate). Where less heat is requiredby the heating accessories, either the temperature of the heating fluidmay be reduced, the flow rate of heating fluid may be reduced, or acombination of both may be used. A reduction in the flow rate isparticularly advantageous as it results in a lower temperature of thereturning heating fluid, as the temperature of the heating fluid mustdrop further in order to result in the heating accessories being heatedto their respective desired target temperature.

As shown, the heating system 100 includes a plurality of heatingaccessories 108, 110, and 112, respectively. As shown, the heatingaccessories are arranged in series relative to one another, such thatsubstantially all of the heating fluid is delivered sequentially to eachheating accessory. In one embodiment, heating accessory 108 may comprisea heat exchanger configured to heat culinary hot water. For example, theheating fluid from boiler 102 is delivered to the heat exchanger ofheating accessory 108 and heat from the heating fluid is transferred tothe culinary hot water within heating accessory 108. Exchange of heatmay be accomplished by any suitable heat exchanger design (e.g.,counter-current flow, co-current flow), as will be apparent to one ofskill in the art.

The heating fluid is then conveyed to heating accessory 110, which maycomprise, for example, a hot tub. In a similar manner, heat from theheating fluid is delivered into the hot tub so as to raise itstemperature to a desired target level within a heat exchanger associatedwith heating accessory 110. The heating fluid is then conveyed toheating accessory 112, which may comprise, for example, a heatedswimming pool. In a similar manner, heat from heating fluid is deliveredinto the swimming pool so as to raise its temperature to a desiredtarget temperature within a heat exchanger associated with heatingaccessory 112.

Finally, after the heating fluid has been conveyed for use to eachheating accessory, it is returned to boiler 102. As a result of removalof heat at each heating accessory, the heating fluid is significantlycooler when returned to boiler 102 as compared to the temperature of theheating fluid as it leaves boiler 102. At 114 cooled heating fluid isused to condense water vapor out of the flue gas generated by boiler102. Once the heating fluid has been used to condense water vapor out ofthe boiler flue gas, it is then reintroduced into boiler 102, where itis reheated and cycled again through the closed loop of the heatingsystem 100.

FIG. 3 illustrates a more detailed schematic similar to that ofsimplified FIG. 2. By way of example, the temperature of the heatingfluid coming out of boiler 102 may be about 180° F. The targettemperature of heating accessory 108 (e.g., culinary hot water) may bebetween about 120° F. and about 180° F. The target temperature ofheating accessory 110 (e.g., a hot tub) may be between about 100° F. andabout 110° F. (e.g., about 104° F.). The target temperature of heatingaccessory 112 (e.g., a heated swimming pool) may be between about 80° F.and about 95° F. The temperature of water returning to boiler 102 isadvantageously not more than about 120° F. so that it can be used tocondense water out of the boiler flue gas. The flow rate of waterthrough the system is advantageously adjustable at valve flow controller106 to ensure this is the case.

For example, a temperature sensor may be disposed within piping 104(e.g., at a location downstream from the last heating accessory 112) tomeasure the temperature of the heating fluid at this location. If thetemperature is too high then the flow rate of heating fluid throughcontroller 106 may be decreased so as to result in a larger temperaturedrop of the heating fluid through the system. If the temperature is toolow, the flow rate of heating fluid through controller 106 may beincreased, resulting in a smaller temperature drop of the heating fluidas it cycles through the heating system.

In a preferred embodiment, the system may be capable of a variable flowrate turn down ratio of at least about 5:1, more preferably at leastabout 10:1. For example, a suitable variable flow rate boiler having aturn down ratio of about 15:1 is available from Aerco International,Inc., located in Northvale, N.J. Aerco's BENCHMARK series of boilers areexamples of boilers having suitable characteristics.

The present invention can be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. Thus, thedescribed implementations are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

1. A heating system, comprising: a boiler comprising a heat exchangerfor heating a heating fluid; a plurality of heating accessories eachrequiring input of heat; piping connecting the boiler with the heatingaccessories, at least one of the heating accessories being placed inseries relative to at least one other of the heating accessories; avalve system including a variable speed pump for varying flow of theheating fluid from the boiler through the piping to the heatingaccessories; each heating accessory being configured such that heatingfluid from the boiler and delivered through the piping to eachsuccessive heating accessory in series provides heat to each heatingaccessory and the heating fluid is returned to the boiler at asufficiently low temperature so as to allow the returned heating fluidto be used to condense water out of flue gas generated by the boiler soas to maximize an efficiency of the boiler.
 2. The heating systemrecited in claim 1, wherein all of the heating accessories are placed inseries relative to one another.
 3. The heating system recited in claim2, wherein each heating accessory is heated to a desired targettemperature by the heating fluid from the boiler.
 4. The heating systemrecited in claim 3, wherein a heating accessory having the highesttarget temperature is placed first in the series of heating accessoriesand a heating accessory having the lowest target temperature is placedlast in the series of heating accessories.
 5. The heating system recitedin claim 1, wherein the heating fluid is returned to the boiler at atemperature of no more than about 120° F. so as to allow the returnedheating fluid to be used to condense water out of flue gas generated bythe boiler so as to maximize an efficiency of the boiler.
 6. The heatingsystem recited in claim 1, wherein the heating system is a closed loopsuch that substantially all heating fluid leaving the boiler is returnedto the boiler.
 7. The heating system recited in claim 1, wherein thevalve system including the variable speed pump further comprises atemperature sensor configured to measure the temperature of heatingfluid returning to the boiler and wherein: the variable speed pumpincreases a flow rate of heating fluid out of the boiler and through theheating accessories if the measured temperature of the returning heatingfluid drops below a desired target temperature; and the variable speedpump decreases a flow rate of heating fluid out of the boiler andthrough the heating accessories if the measured temperature of thereturning heating fluid rises above a desired target temperature so asto maintain the temperature of the returning heating fluid within adesired target range.
 8. The heating system recited in claim 7, whereinthe heating fluid is returned to the boiler at a temperature of no morethan about 120° F.
 9. A heating system, comprising: a boiler comprisinga heat exchanger for heating a heating fluid; a plurality of heatingaccessories each requiring input of heat; piping connecting the boilerwith the heating accessories, at least one of the heating accessoriesbeing placed in series relative to at least one other of the heatingaccessories; each heating accessory being configured such that heatingfluid from the boiler and delivered through the piping to eachsuccessive heating accessory in series provides heat to each heatingaccessory and the heating fluid is returned to the boiler; a valvesystem including a variable speed pump for varying flow of the heatingfluid from the boiler through the piping to the heating accessories; atemperature sensor operatively coupled to the valve system, thetemperature sensor and valve system being configured to measure thetemperature of heating fluid returning to the boiler increase ordecrease a flow rate of heating fluid out of the boiler to the heatingaccessories so as to maintain a temperature of the heating fluidreturning to the boiler within a desired range so as to allow thereturned heating fluid to be used to condense water out of flue gasgenerated by the boiler so as to maximize an efficiency of the boiler.10. The heating system recited in claim 9, wherein all of the heatingaccessories are placed in series relative to one another.
 11. Theheating system recited in claim 10, wherein each heating accessory isheated to a desired target temperature by the heating fluid from theboiler.
 12. The heating system recited in claim 11, wherein a heatingaccessory having the highest target temperature is placed first in theseries of heating accessories and a heating accessory having the lowesttarget temperature is placed last in the series of heating accessories.13. The heating system recited in claim 9, wherein the heating fluid isreturned to the boiler at a temperature of no more than about 120° F. soas to allow the returned heating fluid to be used to condense water outof flue gas generated by the boiler so as to maximize an efficiency ofthe boiler.
 14. The heating system recited in claim 9, wherein theheating system is a closed loop such that substantially all heatingfluid leaving the boiler is returned to the boiler.
 15. A heatingsystem, comprising: a boiler comprising a heat exchanger for heating aheating fluid; a plurality of heating accessories each requiring inputof heat, each heating accessory being heated to a desired targettemperature by the heating fluid from the boiler; piping connecting theboiler with the heating accessories, each of the heating accessoriesbeing placed in series relative to one another in which the heatingaccessory having the highest target temperature is placed first inseries and the remaining heating accessories are placed in order ofdecreasing target temperature; each heating accessory being configuredsuch that heating fluid from the boiler and delivered through the pipingto each successive heating accessory in series provides heat to eachheating accessory and the heating fluid is returned to the boiler; avalve system including a variable speed pump for varying flow of theheating fluid from the boiler through the piping to the heatingaccessories; a temperature sensor operatively coupled to the valvesystem, the temperature sensor and valve system being configured tomeasure the temperature of heating fluid returning to the boilerincrease or decrease a flow rate of heating fluid out of the boiler tothe heating accessories so as to maintain a temperature of the heatingfluid returning to the boiler within a desired range so as to allow thereturned heating fluid to be used to condense water out of flue gasgenerated by the boiler so as to maximize an efficiency of the boiler.16. The heating system recited in claim 15, wherein the heating systemis a closed loop such that substantially all heating fluid leaving theboiler is returned to the boiler.
 17. The heating system recited inclaim 15, wherein the plurality of heating accessories include culinaryhot water having a highest target temperature, a hot tub having a secondhighest target temperature, and a swimming pool having a lowest targettemperature.
 18. The heating system recited in claim 15, wherein thetarget temperature of the culinary water is between about 120° F. andabout 180° F., the target temperature of the hot tub is between about100° F. and about 110° F., and the target temperature of the swimmingpool is between about 80° F. and about 95° F.
 19. The heating systemrecited in claim 15, wherein the heating fluid comprises heating waterand each of the heating accessories comprises a heat exchanger andfurther comprises water requiring input of heat in order to reach thedesired target temperature, the heating water from the boiler heatingthe water of each heating accessory to the desired target temperaturewithin the heat exchanger of each heating accessory.
 20. (canceled)